The Identity of Crambe suecica (Brassicaceae), an Obscure Garden Plant That Caused Nomenclatural Chaos in Taxonomic Botany

Plant species established on the basis of early garden cultivation may have lacked the original information about their native geographical origin. Crambe suecica was originally described from its 18th-century cultivation in the Chelsea Physic Garden in London, raised from seeds without provenance that were sent from Saint Petersburg. This species has been misunderstood as native to the Baltic Sea coasts and, consequently, misinterpreted as a taxonomic synonym of C. maritima. We infer from plant morphology and the history of Russian botany that seeds of C. suecica were originally collected by Johann Christian Buxbaum in 1726 when he travelled across the Ottoman Empire and then-Russian Transcaucasia, most likely in the Gilan or Mazandaran provinces of present-day Iran. According to the morphology of its type specimen, this taxon represents a glabrous variant of C. orientalis and is hereby reduced to a synonym of the latter species. The name C. pinnatifida has been misapplied to a species native to south-eastern Europe and the north-western Caucasus. This species name is nomenclaturally superfluous and illegitimate because its protologue includes a reference to C. suecica, which is to be treated as its type-bearing synonym. This case underlines the importance of historical research in nomenclatural studies, which may be required to reach a correct taxonomic decision.